Method for estimating repair accuracy of a mask shop

Abstract

The present invention provides a method for estimating repair accuracy of a mask shop. The method comprises the steps of providing a mask having a light-shielding layer with a pattern of a plurality of lines, each of which has a defect, using the mask shop to repair the defects. Contaminated areas are formed in the vicinity of areas where the defects are repaired, measuring first light intensities of the contaminated areas, and second and third light intensities of two sides of the contaminated areas, and calculating ratios of means of the second and third light intensities to the first light intensities to estimate the repair accuracy.

1. A method for estimating repair accuracy comprising the steps of:
 providing a mask having a light-shielding layer with a pattern of a plurality of lines, each of which has a defect;  
 repairing the defects, whereby contaminated areas are formed in the vicinity of areas where the defects are repaired;  
 measuring first light intensities of the contaminated areas, and second and third light intensities of two sides of the contaminated areas; and  
 calculating ratios of means of the second and third light intensities to the first light intensities for estimating the repair accuracy.  
 
     
     
       2. The method as claimed in  claim 1  further comprising the step of:
 calculating a mean and 3 sigma value of the ratios.  
 
     
     
       3. The method as claimed in  claim 1  wherein the lines comprise a plurality of vertical and horizontal lines. 
     
     
       4. The method as claimed in  claim 3  wherein widths of the lines range from 0.5 μm to 2 μm. 
     
     
       5. The method as claimed in  claim 1  wherein widths of the defects along the lines range from 0.3 μm to 1.5 μm. 
     
     
       6. The method as claimed in  claim 1  wherein the defects are indentations on the lines. 
     
     
       7. The method as claimed in  claim 1  wherein the light-shielding layer is a chrome layer.